


Three Sided

by Grotesque (Grotesque_Flower)



Category: Gravity Falls
Genre: Anal Fingering, Fluff, I suppose it is, M/M, Masturbation, Merry Christmas btw, Sex Toys, Triangle Bill Cipher, Triangular!Bill, dirty talk - sorta, i cannot fucking believe i wrote this..., i dont know what to tag this as tbqfh, this title sucks im so sorry, triangle fingering, triangle!Bill
Language: English
Status: Completed
Published: 2015-12-26
Updated: 2015-12-26
Packaged: 2018-05-09 11:43:52
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,421
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5538608
Author URL: https://archiveofourown.org/users/Grotesque_Flower/pseuds/Grotesque
Summary: <blockquote class="userstuff">
              <p>The night the two had planned, well had a few set backs, well one actually; Bill had worked himself too hard to be able to retain his human form. But Dipper doesn't mind a single bit.</p>
            </blockquote>





	Three Sided

**Author's Note:**

> what the fuck is this awkwardburgerpantssmile.jpeg
> 
>  
> 
> I cannot, for the life of me... Think of a title that doesn't sound completely dumb and ridiculous.

Dipper stood awkwardly in his room, the door locked and the entire house vacant aside from himself. He shifted his weight from foot to foot as he spoke out into the empty room, “Bill, come on… I did this for you…”

It wasn’t a secret in their relationship that the demon had acquired an… Interesting love of Dipper wearing feminine undergarments. While it started out simply it had grown to where it was now; the mortal standing in the room wearing a pair of stockings stretched over his legs and held up by two garterbelts, lacy blank panties and a harness belt that wrapped around the smallest point of his torso and had two belts in the front and two in the back that connected down to the lower garterbelt. He’d be lying however if all this didn’t make him feel, well, oddly attractive for some reason unbeknownst to himself.

He huffed and folded his arms over his chest as he narrowed his eyes at nothing, “Bill if you don’t come out right now I’m taking this all off and I’ll go do something else instead of spending intimate time with you.”

“Wait,” finally the familiar voice of the demon rang through his ears, but he wasn’t anywhere to be seen, “Don’t do that…”

“Come on then, stop playing that weird demon game of ‘I can see you but you can’t see me’ junk,” he scanned his dark hazel eyes around the room as he tried to find him.

“But I’m relatively comfortable right here; how about we do that kind of scenario where we both know I’m watching but you act like you’re alone? You like that, right?”

“Maybe, but that’s not what you said the other day,” Dipper’s voice was in a mock pout, “You said we’d be together, no games, just me and you.”

“I know what I said! But when am I truly true to my word? I change my mind all the time…”

“Bill…” Dipper sighed, “I’m going to get dressed…”

“No! No, okay okay, fine, sheesh kid…” He could hear the other sigh, an underlying emotion in his tone that he couldn’t quite place, “Besides though, Im already in the room.”

“Come out where I can see you then, I’m giving you ten seconds before I’m changing.”

 He heard Bill whine in a barely audible tone before he felt warm hands against his shoulder, his hands were smaller than usual but he didn’t think anything of it. When he went to turn around the demon clung to him, moving with him to stay out of view.

“Bill,” Dipper hummed in annoyance, why the demon was acting the way he was beyond him truthfully. But he grabbed one of the hands at his shoulder and held onto it, spinning himself around to look at his demon, “Bill?”

“I swear to God Pine Tree if you laugh I will burn you…”

Bill crossed his arms. He wasn’t his usual human-like appearance Dipper had grown used to over the course of many years, but instead he was back in that triangular form he had when they first met in the very beginning of it all. His gaze averted as a faint twinge of an embarrassed hue picked up just above his bow tie.

He didn’t laugh, but gave him a soft smile as he looked at him, “Bill, I’m not gonna laugh. But I do have to ask what’s up with you being, well, in your dream form?”

“I worked too much.”

“What do you mean?”

The demon squeezed his eye shut as he sighed, looking at his human, “I wasn’t paying attention and I’ve been over working myself. I don’t have enough energy to retain a human form right now, I have to wait and focus my magic and energy on that so I can be- well the Bill that you actually like…”

Dipper rolled his eyes, grabbing a hold of the other and pulling him closer so he could place a kiss to what he assumed to be his forehead, “Bill, you are always the Bill that I like, geez you’re so weird sometimes.”

“Don’t flatter me, nobody is attracted to triangles,” Bill rolled his eye at his words, batting him away with his thin hand to add space between them.

“I don’t know,” Dipper shrugged, “I’m pretty attracted to your triangle form; you have all the right angles.”

Bill’s breath hitched when Dipper smiled at him, bringing a hand up to slowly trace down one of his sides, “I-I’m not an equilateral, geez, I’m a isosceles, didn’t you learn about shapes in sc-hOOl…?”

“What was that?” Dipper blinked at the way his voice cracked when he continued to drag his fingertip down his side, giving him a curious look.

“I asked you a question first,” Bill pushed his hand away from him and crossed his arms, floating up out of his reach to prevent further touching at the moment, pulling out his cane to point at the mortal, poking his nose, “Didn’t you learn about shapes?”

“I was trying to compliment you, but obviously you’re more defensive in your normal form than not,” he smiled at him with a narrowed gaze, “Now answer mine; what was that thing with your voice?”

The demon simply flushed, getting his human to smile widely at him, almost happily, “Oh my God I remember! I totally forgot how sensitive your sides are! It’s been years since you’ve been in this form…”

“Ugh, let it go or whatever,” Bill pulled his cane back and twirled it with his fingers, “It doesn’t even matter right now, I’m gonna focus on getting’ my human form back and when I do it’s goodbye sensitive sides.”

“It does matter…” Dipper looked up at him and tried to tug the semi-long lace hem of the garter harness around his hips down, as if to cover himself, “You said you didn’t want me to change, and I said I wanted to see you.”

Bill looked down at him wide-eyed with slight confusion, holding his cane still, “You… Still wanna do that even though I’m not, human-like…?”

“Come here,” he gave him a small, reassuring smile. And the demon did, slowly moving down into reach and being carefully tugged closer by his human. Dipper hummed as he smiled, taking hold of that odd little gravity-defying top hat and removing it from the demon, getting a small ‘hey’ in response, “It doesn’t matter how you look, because I love you for you, and right now you _are_ you,” he gave him a mock kiss, “Now come on, well unless you don’t want to…”

“I do,” his gaze softened greatly, his voice quieter than his usual amplified volume, “I just wasn’t sure if you wanted to still…”

Dipper simply smiled at him, still holding his hat in his hand. Bill took in a deep breath and cleared his throat, spinning his cane around his finger, “Well alright then! Come on, let’s get to it, kid! Keep giving me those kisses will ya? You’re making up for my lack of mouth at the moment.”

“Right,” Dipper followed him over to the bed, “You want to focus your magic on the body thing, right?” he got a verbal ‘yes’, “Alright, so our rule for tonight is no magic. None at all, not even magical words, runes, anything like that.”

Bill turned around to look at his human skeptically, “hmmmmmmmm…. Fine, okay, alright yeah, whatever. I can still do all my normal, well most of my normal routines here without my magic.”

His human smiled at him, kissing just below his eye as he brought his hands up to his tie. He fumbled with the fabric for a moment before it unknotted, he carefully tugged at one end as it was ran through Bill’s form, almost as though it was single stitched through to stay in place. It got the demon to slightly blush, but not at the action but more at the result of the tie being taken off.

He allowed Dipper to take his cane away and set all three on the desk, “I feel so incredibly naked right now…”

“Damn Bill, look how lewd you look, no tie or hat on, scandalous,” Dipper shook his head with a smile.

The demon didn’t answer, instead he gave a soft glare at him as he climbed onto the bed. Dipper sat with his legs crossed and he pulled Bill into his lap, already keeping his words as he began to pepper his form with kisses. His heat radiating from him and seeping onto his lips with every kiss. He supported the demon by locking his fingers together behind him, allowing him to lean back as he was given the affection he requested- if he had a mouth he would be smiling ear to ear as he giggled softly. Dipper smiled against his surface at the happy sounds. He decided to bring one hand to the other’s side and rest there, using his thumb to gently rub up and down in short motions. It was enough to get Bill to sigh already at the soft but pleasant touch. The demon opened his eye and looked down, scooting closer to his human so he could do the same and trace his smaller hands up and down his bare sides to get the sighed reaction he had given.

Bill pushed Dipper’s hands away from him and pushed against his chest so he would get the point. When Dipper did he leaned back, allowing the demon to kneel on his torso as he stared at his chest in a determined focus. Trying to figure out what exactly he wanted to do and how he was going to do it without a mouth to do so. The lightbulb shone brightly as he smile with his eye, bringing his fingertips to his human’s collarbone and digging them into his flesh momentarily. Dipper gave him a confused look but didn’t question as he moved till his hands were at the hinge of his jaw, he moved his thumbs in soft circular motions as he slowly moved his hands down the side of his human’s throat, digging his nails into the more sensitive areas and getting his breath to hitch. Dipper’s eyes slide closed and head tilted back when he felt those hands at the base of his neck and shoulders, thumbing the dip between his collarbones.

“You know, Pine Tree, it’d be _real_ easy for me to have you a begging mess underneath me, even in my normal form,” Bill’s voice was low as he continued to tease the sensitive patch on his neck, “In fact that’s what I had planned originally for you tonight; A whining, drooling, horny and needy little kitten. Clawing the bedsheets as you’d moan every single name and title you could figure out to call me until I’d give in and do everything you wanted me to do to you.”

Dipper whined as the words hit his eardrums and registered, sending heated shivers down his spine. Feeling Bill move back on his chest to trail his hands down lower as he spoke, teasing him both verbally and physically with those damn hands of his, “I’ll have to make up for my lack of mouth later. I promise. I’ll bite you, because even though you say you don’t like it I know what’s going on in that head of yours. You love it, you love it when I mark you, especially in places that everyone else can see. You like it rougher, don’t you?”

He waited but didn’t get an answer, but it wasn’t really like Dipper was aware he actually was expecting one until he felt his nails dig into his skin as hard as he could, getting a sharp gasp from the man underneath him and hast nod, “Y-yeah, yes I do like it rough, I love it!”

Bill unlatched his nails and ran his hands flat over the indents his nails left, “I know… I do too. You know what I also love though?”

“W-what?”

He hummed and turned around, scooting down until he could slip his hand underneath the belt around his human’s waist, giving it a hard pull, “I love it when you dress up for me, just like this.”

“Well,” Dipper took in a sighed breath, “I love dressing up for you, only for you actually…”

“I know you do,” Bill continued to move himself lower, until his sat on the man’s stomach, “Which is a good thing, because I wouldn’t want anyone else seeing you like this. You know, this is for my eyes only.”

Dipper wasn’t expecting Bill to be working so fast, but it made sense with the lack of anything else to use aside from his words and hands. He felt the demon slip on of his hands over the front of his laced underwear, teasingly kneading his palm there and coaxing him to rock his hips against his hand. It wasn’t as much as Dipper was used to, but damn did he enjoy it nonetheless, enjoying the way his demon brought both his hands up to rub him through the thin layer of clothing.

“You know, Sapling, it’s a shame,” Bill sighed, but never stopped his handwork, “I was thinking of sucking you off tonight, I don’t do that very often, but you always like it so much and you’ve been so _good_ lately, I wanted to treat you with it… Oh well…”

He whined in disappointment, he wasn’t sure if he was lying or not but he didn’t care at the moment, the false promise of his mouth around his dick sounded… Fantastic truthfully.

And then Bill pulled his hands away, getting him to whine even louder, “Oh, what? Am I not enough just like this?”

“What…?” Dipper leaned up on his elbows, seeing how Bill had moved to sit facing the wall with his arms crossed over his form.

“You want my mouth, but I’m all I am right now, is that not good enough for you?”

His eyebrows knitted in confusion, “But… I didn’t.. I didn’t say that. Bill you’re doing great! I love it so much!”

“Well obviously you don’t need _me_ to get you off,” Bill sighed and moved off of him completely. Dipper blinked once or twice before slowly understanding what the demon was getting at, swallowing as he allowed him to continue anyway. His cat-like pupil flickered to him, “Go get it.”

And he didn’t need to be told twice. Dipper quickly got up from the bed and over to the closet, opening it and already digging through the mess he had shoved in there throughout the days until he found what he was looking for. Rummaging through his backpack until he found one of the toys, deciding it was good enough, and the bottle of lube before shoving the bag back into the small storage and not even bothering to close the door. Bill watched with a bored expression as Dipper bit his lip, debating on what he truly wanted to do. His gaze flickered to the demon.

“Well, go ahead, show me what you can do.”

Dipper nodded coyly. Kneeling on the bed as he decided to slip his hands beneath the hem of his underwear to fully touch himself, his eyes sliding closed as he did so. He leaned forwards on one hand as he awkwardly pumped along his shaft, teasing himself to his full arousal. Reluctantly he pulled his hand away, sitting back on his tailbone as he shimmied out of the panties. Once he did he looked over at Bill, who locked eyes with him and still held that bored expression, his breath catching in his throat. He didn’t want to waste any more time. He moved himself to lay against his pillow, grabbing the lube and pouring what he need onto his fingers before closing the bottle and putting it aside. He moved his hands down and went right to pushing the first finger inside of himself.

As he moved the first finger slowly he decided to whisper a laugh out of nervousness, “I-I don’t think I can do this, like you do… You’re so much better at this than me…”

Bill perked up slightly, not that he wasn’t interested before, trust him he was. But the sudden words came as an unexpected surprise and made him falter his decoy of not caring, “Really now?”

“Yeah…” Dipper spread his legs more as he curled his finger enough to slip his middle finger inside, scissoring once or twist and then shifting his hips a bit and doing the same again.

He swallowed hard as he squeezed his eyes shut, focusing on stretching himself with his fingers enough to slip the third one in to join. Curling and uncurling, flicking his wrist so he could thrust his fingers and try to find his sweet spot. He would quietly mewl as he’d push his hips back, raising them to get a better angle before he decided he had enough of it and pulled them out. He opened his eyes lazily to look for the toy and once he found it he did the same and coated it with enough lube, this time carelessly tossing the bottle aside as he pressed the toy against himself.

He smiled over at Bill shyly as he pushed it inside of himself, “Y-you kno-w… You already know, but… I always like to think that it’s- you doing this…”

Bill moved closer to him, placing a hand on his human’s thigh, “Hmmm, what do you mean by that?”

“Like,” He let out a heavy sigh when the toy was completely inside of himself, waiting a moment or two as he spoke, “Even if it’s not, thinking about you fucking me. I imagine it’s you holding the t-toy for me, teasing me… Getting me to cum with just some vibe or something, God is it great though… It’s so much better than just thinking about getting off- thinking it’s _you_ is, fucking fantastic…”

If Bill could he would have licked his lips at the comment, instead he dug his fingertips into his human’s flesh as he watched his face from the corner of his eye. Dipper sighed heavily as he pulled the toy back and slowly pushed it back in, raising his hips and squeezing his eyes tightly. Bill watched with a lidded expression as the man set a pace quickly, a steady flickering of his wrist but pushing the toy harder inside of himself, Bill could hear his racing thoughts over his hiccupped gasped mewls and whines.

Dipper sighed heavily as he shifted his hips more and changed the angle of his hand, “S-shit, Billl, ho-how do you, fuck, how do you move…? I can’t mimic it… It’s nothi-ng like you at all…”

Bill’s features had a glowing redish pink hue, “Does it feel good?”

“Y-yeah, but- not as good as you thou-ough…”

The demon swallowed as he whispered, “Okay… hold on, I can make you feel good in a sec-“

“B-ill, I said no magic….” Dipper stopped his movements to look down at him.

Bill had his hand raised to summon whatever it was he was going to do, when he heard both the voice and noticed the halted movements he looked over at him with a flushed confused expression before he lower his hand back down, “R-right… Okay, yeah. Let me do something else then.”

He moved to sit on the mortal’s lower abdomen, straddling him almost as he grabbed the base of Dipper’s cock with his hands. With the first upward pump the man decided to begin to move the toy again, picking the pace up again and shifting his hips to brush his sweet spot as best he could, trying not to kick the demon off him as he worked on his cock. Bill was focused, listening to the soft moans and the vivid thoughts that Dipper had. Doing his best to get him off. Somewhere along the way their movements had synced, and though Bill could tell, Dipper was in bliss in the moment. Whining out encouragement to the demon, to keep moving his hands like that, and when he would tease the underside of his cock’s tip he’d get a low moan and a buck into his hands, spurring him on more.

Dipper wasn’t sure what to focus on; the demon’s hands, his own thoughts and imagination, or even the toy. But he couldn’t care at this point, he was close, too close. Feeling his orgasm build up with every touch and every hard thrust. His toes curled and his stomach tightened as he came, dipping his head back as a low deep moan fell from his lips, “Oo-oh, fu-ck, Bill~….”

When the demon stopped his hands he eyed the mess but didn’t say anything of it, simply allowing Dipper to take his breathing before he sat up. He was about to move off his lap when he felt an arm hook around him, the human’s other arm moving to pull the toy out of him and moved it to be dealt with later. Bill squirmed to flip around in his lap, looking up at him.

“H-hey,” Bill spoke when Dipper hummed and ran both his hands up his sides, getting him to emit a darker shade of the red-pink hue, “What are y-ou, doing?”

“Taking care of you, shush,” and that was that. Bill shut himself up as he felt the other begin to pepper him with kisses again.

Trailing his fingertips down Bill’s sides until the base and getting him to shudder under his touch, he would bring his fingernails upwards in a ginger touch. It was such a simply action but it had the demon squirming in his arms, trying to climb out of his lap after a while. But Dipper held him in place, feeling his hands push at his arms as he turned away only to regret it instantly.

“O-oh good Go-d…” Bill breathed heavily, digging his fingers into the man’s arms when he felt his warm tongue lick up his side slowly.

He squeezed his eye shut and stopped squirming, tensing as he was held close to his human. Dipper teasingly flicked his tongue against him as he brought one hand around to rub against his other side. Bill moaned quietly when he felt him actually begin to kiss a trail down his side, nipping and licking along the way. His fingers along the other side would rub harsher every now and again, getting him to squirm in his lap. Finally Bill turned again to face him completely, his entire form a red-pink as he looked at him with lidded eye.

Dipper kissed his eye, forcing him to close it, “Tell me what you need…”

Bill didn’t care speak what it was he wanted from him. So instead he took hold of one of his human’s wrists and carefully guided him to his lower side, getting Dipper to furrow his eyebrows in confusion, “Wait what?”

“J-just, two fingers, just do it… Okay…?” his embarrassed scowl was gone, and replaced with a needy look at he stared at him.

Dipper didn’t say anything else and decided to just do as he was told, though he didn’t see how it’d even work or what it was he was even doing. He watched with curiosity as he pushed two fingers against Bill’s lower side, raising his eyebrows when they actually went inside of him. Was that even possible? Well apparently it was. It was, a peculiar feeling, almost indescribable. It was a burning feeling, but also a freezing feeling. A static pins and needles, but also a numb feeling. It was perplexing, and the look on Bill’s face told him that it must have felt good for the demon. Bill had his eye closed, relaxed completely in the other’s arm. Dipper worried his lip for a moment before deciding to move his fingers, curling them to see what sort of reaction he would get. Bill arched and hissed a bit at the now unfamiliar feeling of it all. But he quickly got used to it, shifting himself against the man’s fingers more and more as he whined.

“F-uck, Dippe-err,” his voice was low and breathy, dripping with need. It urged Dipper to push his fingers more, pulling them out and then back in, much like he did himself or when Bill would do it to him.

Bill opened his eye halfway, pupil blown with lust. He lazily gestured to his face as if to say ‘kiss?’ and Dipper happily obliged, leaning forwards while never stopping his fingers to give his demon sloppy open mouth kisses. Bill pushed up into the kisses as if to return them, pushing back also on his human’s fingers as he felt himself get hotter. Shit… With a low moaned-whine of Dipper’s name, Bill squeezed his eye shut again, drawing out his gasp as his limbs were quickly enveloped with the electric blue flame that ate down his arms and legs before tapering off into nothing. But it left Bill exhausted, completely limp against Dipper now as said man pulled back to look at the way he tiredly blinked at him. Carefully Dipper pulled his fingers out of him and moved them around, cradling his demon close to his chest.

Once he was on his back and under the covers, really not at all caring about clean up or anything at the moment for that matter, Bill nuzzled into his chest as he laid on top of him, finally finding his voice and speaking lazily, “Once I can retain my human form, I am going to give you so many kisses, you’ll forget how to count.”

Dipper laughed, “I’ll hold you up to that one.”

“I know you love kisses,” he sat up on his hands as he moved close to his human’s face, smooshing their faces together in a make-shift kiss, “But I gotta rest so I can keep that promise.”

Dipper placed a kiss above his eye, “I know, we both need to rest for now, okay?” Bill laid back down on him, snuggled closer this time to his jaw, “I love you though Bill… Triangle or other.”

“And I love you too, Pine Tree or other.” He heard Dipper snicker at the comment, but didn’t reply, instead snuggling more into him as the entire toll of his exhaustion began to heavily set in.

**Author's Note:**

> Do. Not. Finger. A. Triangle.  
> Ever.  
> Do not. I swear to God if you do so i will scream.
> 
> Why did i write this, seriously why did i write this. I was thinking about it the other day, i was gonna have tentacles come into play, but then on the drive home from a christmas party i thought "No, no tentacles. Let's have Dipper finger Bill Ci the Triangle Guy."
> 
> Grammar mistakes and spelling errors, please point them out UoU
> 
> K/C/B/Etc~!! <3 ^_^


End file.
